It’s always nice to be truly, genuinely surprised by a movie. It doesn’t happen all that often, so when it does, it’s a treat.

For instance, the most delightful surprise of 2016 was the ending of M. Night Shyamalan’s “Split,” whose closing scene revealed it to be part of the same universe in which his 2000 film “Unbreakable” took place.

A surprise sequel? To a movie that I personally loved and whose deconstruction of the superhero predated the MCU-led super-movie explosion of the last decade or so? Yes, please.

And of course, the series – dubbed the Eastrail 177 trilogy, after the train crash that kicked off the events of “Unbreakable” – must be completed.

“Glass” marks the culmination of a decades-spanning story, one that addresses the aspirational mythologizing behind our fascination with the superhuman. It’s a chance to once again grapple with what a world of heroes and villains might actually mean – both to them and to the rest of us.

While “Glass” has its share of flaws – namely Shyamalan’s inability to fully divest himself of some of his more self-indulgent tendencies – it is still a worthwhile final installment. The ethical ambiguity of heroes and villains, the general implications scaled both small and large – those are here, albeit occasionally a bit muddied. And with some top-notch performances and a handful of sharp aesthetic choices, the movie succeeds far more than it fails.